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In-situ temperature XRD and mechanical spectroscopy were applied to study phase transitions in AuCu alloy from the disordered FCC state (A1). The phase transition temperature intervals were investigated upon heating and cooling using a rate of 1 K/min in order to be thoroughly determined. The following sequences of phase transitions were recorded upon continuous heating: A1->AuCuI ->AuCuII->A1 and on subsequent cooling: A1 ->A1+AuCuI+AuCuII ->AuCuI+AuCuII ->AuCuI. This transition sequences determine also temperature dependency of elastic and anelastic properties. Mechanical spectroscopy using a forced torsion pendulum shows a peak due to antiphase boundaries motion characterizing the orthorhombic phase AuCuII and a transient peak with the that appears in the tetragonal phase AuCuI together with the classical Zener peak in the A1 phase.

Phase transitions in AuCu alloy are investigated using in situ temperature XRD and mechanical spectroscopy. The measurements are carried out from room temperature up to 973 K starting from the ordered phase AuCuI. Using a temperature ramp rate of 1 K/min, the following phase transition sequence was recorded on heating: AuCuI - > AuCuI + AuCuII- > AuCuI + AuCuII + A1 - > AuCuII + A1 - > A1. The mechanical (elastic and anelastic) properties are determined by this phase transition sequence. The mechanical spectroscopy, using a forced torsion pendulum, shows a peak due to antiphase boundary movement in the orthorhombic phase AuCuII according to the temperature dependent internal friction tests. The isothermal frequency measurements show several thermally activated peaks in the phase transitions intervals.

A novel hybrid compound, based on iron, fluoride and 8-hyroxyquinoline, and formulated as (8HQN)6[Fe4F18] (QF1), has been obtained by hydrothermal method and characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), Hirschfeld surface, IR spectroscopy, photoluminescence (PL), thermal analysis and magnetic study. (QF1) crystalizes in trigonal space group R3c with cell parameters a = 17.9239(5) Å, b = 17.9239(5) Å, c = 30.6196 (11) Å, V = 8519.1(5) Å3, and Z = 6. The crystal structure of (QF1) is built up from isolated tetramers [Fe4F18]6− surrounded by six cations 8HQN+. The cohesion between these entities is performed via NH⋯F and OH⋯F hydrogen bonds to form a three-dimensional network. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. IR spectra confirmed the presence of 8-hydroxyquinoleine molecules. The photoluminescence studies of (QF1) show a significate green emission at 2.14 eV associated with radiative recombination of excitons confined within the organic part when it was excited in UV–visible wavelength in the solid state at room temperature. Finally, the magnetic analysis shows that (QF1) has a paramagnetic behavior above 100 K.

The hydrothermal synthesis and the chemical-physical characterization of an ammonium-chromium(III)-iron(III) bis(hydrogenphosphate), Cr0.34Fe0.66NH4(HPO4)2 [CrFeNP] is reported. It was obtained in aqueous media by reaction between chromium(III) chloride, iron(III) chloride, urea, and orthophosphoric acid. The crystal structure of CrFeNP was determined from single-crystal X-ray diffraction data. It crystallizes in the triclinic system, space group P-1, and exhibits two types of different infinite tunnels along [0 1 0] and [1 0 0] directions, where the ammonium cations are located. Thermal analysis shows that the solid is stable up to ca. 600 K. The activation energy of the thermal decomposition up to 1273 K was computed by isoconversional methods. In addition, the magnetic behaviour of the material was investigated from magnetic susceptibility and magnetization measurements. CrFeNP undergoes two successive magnetic transitions at temperatures Tc = 17. 9 K and Tt = 3.1 K, which could be related to a ferri- and an antiferromagnetic magnetic phase transitions, respectively.

Crystalline powder aggregates of a new nickel coordination polymer with 2-carboxyethylphosphonic acid (HPPAH) and 4,4′-bipyridine, Ni(HPPA)(4,4′-bipy)(HO), has been obtained by hydrothermal synthesis, and their crystal structure has been ab initio determined from synchrotron powder data. The compound shows a layer structure in bc plane, with Ni atoms in two different environments. The loss of the coordinated water by heating leads to the apparition of an anhydrous phase, which remains stable when cooling down to room temperature. Synthesized material presents a paramagnetic behaviour with weak antiferromagnetic interactions and zero-field splitting at low temperature (T < 50 K).

Single-phase Cr doped zinc ferrites have been synthesized by hydrothermal method. The crystal structure, microstructure, crystallite size and distribution, composition and magnetic properties of the synthesized nanoparticles were determined using X-ray powder diffraction, electron microscopies and vibrating sample magnetometry. Powders are composed of ultrafine spherical nanoparticles with a highly homogeneous elemental composition. The nanoparticles have partially inversed cubic spinel structure with average crystallite size below 10 nm. Superparamagnetic behavior is observed at high temperature while ferrimagnetic ordering and surface spin canting is reported at 5 K. Substitution of Fe with Cr ions controls both structural and magnetic parameters.